High-frequency electron discharge device and circuits therefor



5 Sheets-Sheet l C. W. HANSELL. HIGH-FREQUENCY ELECTRON DISCHARGE DEVICE AND CIRCUITS THEREFOR March 25, 1952 Filed July 25, 1944 March 25, 1952 Q W HANSELL 2,590,612 HIGH-FREQUENCY ELECTRON DISCHARGE l DEVICE AND CIRCUITS THEREFOR Filed July 25, 1944 3 Sheets-Sheet 2 i JC'IQ. i

INVENTOR ..77 BY) MVM,

ATTORNEY March 25, 1952 c. w. 'HANsELL 2,590,612

` HIGH-FREQUENCY ELECTRON DISCHARGE DEVICE AND CIRCUITS THEREFOR 3 Sheets-,Sheet 5 Filed July 25, 1944 Patented Mar. 25, 1952 erica A.

HGH-FREQUENCY ELEC'IRN DISCHARGE DEVICE AND CIRCUITS THEREFOR Clarence W. Hansell, Port Jefferson, N. Y., assignor to Radio Corporation of America, a corporation of Delaware Application July 25, 1944, Serial No, 546,467

30 Claims. l

This invention relates to high frequency electron discharge devices and circuits therefor, and particularly to a method of and apparatus for converting radio frequency power at one frequency to radio frequency power at a higher frequency.

An object of the present invention is to provide an electron discharge device frequency converter employing a magnetic field, in which the electron emission is utilized more effectively and there is obtained a greater ratio of power output to electron emission than in conventional magnetron circuits.

A further object is to provide a vacuum tube. converter of one frequency to a higher frequency in which a tapered intensity of magnetic eld is employed with an intensity which is less in the region of the anode structure than at either side 'of the anode structure.

A further object is to provide a magnetron type of converter employing a multi-pole anode resonator structure for converting energy of radio frequency to energy of higher radio frequency, and in which a tapered magnetic field is utilized whose intensity is less in the space within the anode resonator structure than at either side of it.

Briefly stated, the present invention employs a rotating space charge continuously moving within a hollow cylindrical multi-pole resonator structure. A tapering magnetic field is utilized whose intensity is less at the location of the resonator structure than at locations at both sides of the resonator structure.

According to one embodiment ofthe invention, electrons are given a high kinetic energy at both ends of the tube and caused to move automatically into the center of the tube where the energy is utilized. The electrons at both ends of the tube are accelerated to high velocities by accelerators driven by radio frequency input power. The accelerated electrons are given a spiral motion of gradually increasing diameter and these electrons are forced bythe tapering magnetic field and by steady state electric fields into the center region of the tube where they concentrate and circulate in orbits within a hollow multi-pole cavityl resonator structure.

I am thus able to separate, physically, the means for accelerating electrons to high velocities and the means for utilizing their kinetic energy. The multi-pole cavity resonator structure functions in the manner of a magnetron' oscillator anode. The frequency of oscillations generated in the centrally located' multi-pole cavity reso.- na-tor structure is approximately a resonant free quency of the cavity, and depends primarily upon the number and dimensions of the poles and secondarily upon the electron velocities. Output power of a frequencyv much higher than the input frequency is derived from the multi-pole cavity resonator structure. Reference is here made to my U. S. Patent No. 2,217,745 for a description of some of the several possible modes of oscillation of such a magnetron structure.

According to another embodiment of the invention, the physical structure of the converter is modified by combining the functions of the accelerators and oscillators into a single electrode structure. This structure is in the form of a circular zig-zag annular metallic ring which excited with two halves in parallel for radio frequency input currents and which has an effective length equal to a number of half waves for the higher oscillation frequency. Here again, a tapered magnetic eld is employed whose intensity is less at the location of the circular ring than at either side thereof for concentrating the rotating electron space charge into the region enveloped by the zig-zag anode resonator structure.

In both of the above mentioned embodiments of the invention, modulation of the output 'amplitude or frequency (independent of the input frequency) may be effected by applying a suitable combination of modulation potentials between the anodes and cathodes, by varying the magnetic eld, by varying the radio frequency 4drive voltage, or drive frequency.

A more detailed description of the invention follows in conjunction with a drawing, wherein:

Fig. 1 illustrates one embodiment of the invention;

Fig. 1c is a modication of the system of Fig. 1 provided with an input direct current voltage between the anode structure and the cathode;

Figs. 2a and 2b show, in detail, cross-sections of the centrally located multiple pole cavity resonator structure with and without a plate closing the ends of the poles;

Fig. 3 illustrates another embodiment ofthe present invention; and I Figs. 4a, 4b and 4c illustrate different types of zig-zag anode structures of annular form which can be utilized in Fig. 3.

Referring to Fig. l in more detail, there is shown an evacuated metallic envelope il) enclosing in the center a multi-pole anode cavity resonator structure l i, and at both sides of the cen `tral structure ll, a pair of electron accelerator ,anode structures i2 and' i3, of smaller size than Athe structure il, symmetrically positioned with respect to the central cavity resonator structure. Each 'of the accelerators I2 and I3 includes a pair of anode segments arranged in the manner of-fasplit anode structure. Segments of the two accelerators are coupled in parallel by means of leads I4 and I5 to a tuned input circuit i S, which in turn is coupled to an oscillator I'I representing a source of radio frequency input power. Tuned circuit I6, with the leads and anode structures connected to it, is tuned to the frequency of the oscillator I`I which may, by way of example only, be 300 megacycles. Surrounding the envelope I are a pair of magnetic eld coils I8 and I9 connected in series relation and supplied with direct current energy from a source of undirectional current 2U. These coils are so arranged that they produce a tapered magnetic eld flux which extends roughly parallel to the cathode 23 and whose intensity is strongest at the locations of the electron accelerators I2 and I3 and weakest (though still strong) at the location of the multipole anode cavity resonator structure II. The dash lines are intended to indicate the tapering of the field with a minimum of intensity at the centrally located resonator structure II. The envelope I is shown connected to ground G by means of a lead 2 I, which connects the envelope to the cathode 23, although if desired the ground connection G and the lead 2| can be replaced, as shown in Fig. la, by a source of direct current voltage 22 placed in series between the envelope, including the anode structure I I, and the cathode. This source 22 of direct current potential illustrated in Fig. lia provides a portion of the input power for both the useful output and the losses. The cathode 23, which includes tensioning springs 4U, passes longitudinally through the center of the evacuated envelope lil and is supplied with heating current from a direct current source 24. It should be noted that the cathode leads and the leads from the electron accelerators I2 and I3 extending externally from the envelope I0 pass through glass seals 25 at both ends of the envelope. I

The electron accelerators I2 and I3 near both ends of the tube function somewhat in the manner of a cyclotron, or a cross between a cyclotron and a magnetron. The anode s-egments of these accelerators may each have a width measured in the direction of the axis which is of the order of the diameter of the split anode structure. The electrons in each of the accelerator structures Atravel circumferentially therein and, due to the strong taperedmagnetic field, are forced outward toward the center of the tube where the magnetic eld is weaker. The electrons in each of the accelerators I2 and i3 are given spiral paths and are accelerated to high velocities by means of the radio frequency input power supplied from the oscillator I'I. The split-anode structure of the accelerators is excited with radio frequency potential at substantially the resonance frequency for electron motion within the axial magnetic eld.

The approximate required relation between the accelerator drive frequency and the strength of the magnetic field, for electron resonance motion, is given in physics text books and is F=2.8H megacycles per second, where H is the magnetic eld intensity in oersteds (Gauss). The energy gained by each electron is approximately the cathode in centimeters. For a resonant irequency cf 300 megacycl-es, according to the example, H :107 oersteds approximately. Ii it is desired that the accelerated electrons reach cnergy levels of say 5G00 electron volts then they must be made to accelerate out to a path diameter of about 4.45 centimeters or 1.75 inches. The diameter of the accelerator electrodes may then be about 2 inches. The inside diameter of the anode structure, where the magnetic field is weaker, may then be about 2.5 to 3 inches.

The electrons in the accelerators follow paths passing around the axis in a spiral of increasing diameter while they are being accelerated. Be-

cause the magnetic field strength is not uniform in intensity along the axis but decreases in intensity toward the center of the tube, the path of each electron will not lie in a plane but will be a spiral starting at some point near the cathode, increasing in diameter during acceleration and moving oi in the direction of decreasing magnetic field intensity. There is thus set up a sort of space charge whirlwind capable o1 charging objects upon which the electrons impinge to negative potentials corresponding to electron energies. Although the two split-anode structures I2 and I3 at both ends of the tube are symmetrically arranged relative to the center of the tube insofar as distance is concerned, they are shown at 96 relation to each other. This physical displacement is made in order to aid in equalizing the space charge distribution around the interior of the central cavity structure II. If desired, both split-anode structures I2 and I3 may be shown arranged similarly without any 90 displacement as shown in Fig. La and small D. C. potential differences between them used to govern the phase relation of groups of space charge arriving inside the anode structure.

The centrally located multi-pole anode cavity resonator structure I Ifollows generally the teachings of my United States Patent No. 2,217,745. When the electron velocities within the anode structure are properly co-ordinated with the resonant frequency of the anode structure by suitable magnetic eld and potential adjustments, oscillations take place which set up waves of variable electron density and space charge in the electron current as well as oscillations ol the electric eld between the anode segments, from which high frequency power may be extracted for signaling or for any other useful purpose.

The high frequency energy is extracted from the kinetic energy oi the moving electrons which slows down the electrons, increases the curvature of their paths and causes them to move back toward the cathode and out along it into the eld of the accelerating electrodes again. By this means, possible when suitable potential adjustments have been made, it is possible to use electrons over and over again in a manner to reduce the required electron emission. The cathode emission required is only that needed to replenish losses of electrons to the electrodes.

The resonant anode cavity II is so designed that the desired resonant frequency causes electro-magnetic waves to travel circumferentially around the poles of the resonant structure II at a velocity which approximatelyI matches the electron Velocity, or else, for another mode of operation, at a velocity which is much slower than the circumferential traveling electrons. In order to assist in raising the velocity and energy level of electrons in the central structure I I, and to add to the effect of the tapered magnetic eld aade 11a incausing'theaccelerated electrons to move into the structure, "it is preferred 4that the anode `II and the metal envelope I0 be polarizedsomewhat 'positive'relative to the cathode in the manner shown in 'Fig 1a by means of direct current volt- -age source p22*. This direct current source 22 of Fig. la" makes little if lany contribution to the linlrut power but does have an eect upon the energy .'leve'l 'at which electrons are utilized in `producing oscillations.

Most vrof the input power is provided by the radio frequency input I'I coupled to the two accelerator split-anode structures I2 and i 3. It will 'thus be seen that in effect there are provided 'twooyclotron accelerators at both ends of the tube and these are utilized to supply most of the 'input' power to the system except the cathode heating power.

Thelength or width of the central cavity structure II in the direction of the axis of the tube Yshou'ldfbe of the order of a half wavelength at 'the output frequency desired, when the ends of thel anode poles are open as shown in Fig. 2b.

"If'the ends of the anode poles of the structure II 'are closed, as for example by means of the 'annular metal plate 25 of Fig. 2a, then the length or width of the cavity structure I in the direction ofthe axis of the tube should be greater than vone-half wavelength but not greater than one wavelength; for example, three-quarters of 'a wavelength. It will be appreciated that in designing the anode structure II it is intended to employ the knowledge acquired from designing more conventional magnetron structures in order to limit the operation of the cavity structure IIto a single mode of oscillations.

Output A from the frequency converter of Figs. 1 and `la may be taken by means of a loop 25 positioned in the interior of the multi-pole anode structure I I and extendingl externally of the envelopeby means of a coaxial line arrangement '21. If desired, output may be derived from the -a-node structure II by means of a wave guide such as-2`I shown in more detail in Fig. 2a. An air sealrinsulator is shown provided between the wave guide '21 and the anode structure II. The

vguide-'2l vis shown in the form of a flange for enablngconnection to a wave guide structure Whichfin 'turn may be coupled to a suitable load and adjustment system. Both these means for coupling to an output circuit are new in wide scale use in' magnetrons used in radar systems.

Letus assume, according to the previous exe ample, that the number of poles of the magnetron anode structure H is 24, thus providing an approximate frequency conversion ratio of when the strength of magnetic iield inside the accelerator electrodes is roughly. 1.2 times that inside the oscillating anode structure. It will be assumed that two adjacent poles of the structure `II are a half wavelength for waves taken circumerentially, although other `modes of oscillation,are possible. Then the desired speed of circling of the axis by the electrons will be 300 megacycles inside the accelerator electrodes, and 250Lmegacycles inside the anode` structure, assuining that the output frequency desired is 3000 mega'cycles. In practice it is thought best to operate the input system a little on" resonance, on a stable side, so thatthe power input source, if it is `an oscillator, will operate in a stable manner. If it is assumed that, due to new emission and recirculation, the total effective electron current owing'inside the magnetron ring structure I`I is as'high as 10 amperes or more at 5000 available to produce the oscillations.

voltsfand'allfelectrons lose an average Tof .10% of 'their energy per revolution 'to theoutput circuit, vthen the tube of the `'example shouldbe capable rof providing outputs up to 5 kilowatts.

As the lhighvelocity electrons travel in spiral paths within `the interior of the anode structure II, theyare crowded to the vicinity of the axis after having lost mostvof their energy to the oscillating iield in the central cavity structure. They are thus forced downward toward the Ycathode 1and then forced by space charge repulsion out into 'thespace between the accelerator electrodes I2 and I3 vand the resonant structure vil and start another cycle of acceleration and deceleration. Therefore, at least in theory, each electron may be used over and `over again, 'and a thermionic cathode is required to supply only enough emission to overcome loss of electrons due to collision with material objects inthe device. It is therefore probable that the number of electrons working at any one time to produce oscillations maybe many times greater than it would be in a conventional magnetron with emission or space charge limiting at the filamentary cathode. Stated in other words, the high velocity electrons after entering the vicinity of the anode structure II first circulate close to the anode surface, but as energy is extracted from them by the oscillation, their paths assume a smaller diameter in the magnetic field so that as a result of losing energy and due to space charge repulsion, and loss of .electromagnetic attraction forces caused by velocity, they are forced inward toward the axis of the tube. In being forced inward to smaller orbits they are forced to 'try to rotate about the axis ata greater rate. This advances 'their phase relation with respect to electrons in surrounding orbits and tends to force them to give up energy to' electrons in the surrounding orbits, thus contributing to energy It should he understood that this 'theoretical explanation is given merely for the purpose of exposition and While believed to be correct it is not of necessity complete, nor doesthe operation of the invern tion depend upon its accuracy or otherwise.

From the foregoing, it will oe seen that the system of the invention illustrated in Figs. l and 1a separate, physically, the `means for accelerating the electrons to a high velocity and the means for utilizing their kinetic energy. Also by exciting the accelerators with radio frequency potentials at a frequency substantially equal to the resonance frequency or electron motion around the axis,foseillations are set up in the central anode structure I i at a higher frequency which is `a function ci the number and dimensions of the poles in the oscillator anode aosembly II. Thus, if the input frequency is 300 megacycles and the anode structure I I twenw ty-four poles and the dimensions of anode structure II accurately designed, it is possible to obtain an output frequency of 3000 megacycles. Similarly, if the input frequency is 300 megacycles and the anode assembly l I has forty poles, it is possible to obtain an output oscillation irequency neal` 5000 niegacycles per second for the mode of oscillation in which alternating magnetron poles oscillare in opposing phase relation. The interconnection cr strappingcf the ends of the poles, as shown in Fig. 2a, enables the number of resonant frequencies in the cathode structure IIto be `limited to the region near the desired output frequency.

It will be noted that there is no exact correlation between-input and output frequencies but only an approximate ratio between them which can be varied over a substantial range of frequency ratios.

Fig. 3 illustrates another embodiment of the present invention which is intended to be a sirnplified construction compared to those of Figs. 1 and 1a. In Fig. 3, the function of the accelerators and oscillators are combined in a single electrode structure. It should be noted that in Fig. 3 there areno separate electron accelerator electrodes as in Fig. l, and that the anode resonator structure 3G consists of a generally zigzag arrangement comprising a multiplicity of poles, bars, teeth or turns arranged in the form of a-n annular ring. This anode structure may takeany one of the forms shown in Figs. 4a, 4b

or 4c. In Fig. 3 there is illustrated an evacuated envelope containing therein a thermionic cathode 4'2 passing longitudinally through the center, a centrally located annular ring constituting an anode resonator structure 3D positioned at right angles to the thermionic cathode, and a plurality of externally located magnetic field coils 3|, 32, and 33. fed generally in series relation from a direct current source 34. The system of Fig. 3 permits a reduction in the length and volume of the frequency converter as compared to the system of; Fig. 1, and also permits sirnplicat-ion such as the reduction in the number of external leads. The field coils 3|, 32 and 33 are so arranged that the magnetic field increases in strength in each direction from the center in the axial direction yfor the purpose of decreasing the tendf ency of the electrons to drift out of the region of the anode structure 3D. The zig-zag anode structure 30 is supplied atpoints A and B with high frequency input power from a source 3d `over leads 35. Points A and B are positioned diametrically opposite one another on the annular ring and are oppositely located with respect to the central cathode or filament. Since the anode structure 30 is an endless zig-zag structure, having the form of either Figs. 4a, 4b,

or 4c, it will be seen that it is excited with two halves in parallel for the input currents. The turns or teeth of the anode structure 3B are identical in dimensions so as to produce a symmetrical structure. The total annular length of the anode structure 39 is preferably equal to a number of half waves, including unity per turn for the oscillation frequency. This anode resonator structure 30 is designed to produce selfmoscillations at a frequency higher than the drive frequency supplied from source 315.. The distance from the center of one bar or tooth of the zigzag anode structure 3l) to the center of the next bar or tooth is preferably one-half wavelength for the output frequency. The bars or teeth are thus in series relation for the input frequency although the two halves of the anode are in parallel for the input currents.

There are, of course, a series of-very high frequencies to which the anode structure is resonant and, in general, a particular resonant frequency is chosen by means of adjustment of the magnetic field, drive frequency and drive potene tial to favor operation at a desired resonant frequency. The selection of a particular frequency may be aided also by suitable adjustments of circuits coupled to the anode structure.

It will be observed that the anode of Fig. 3 is now directly excited from a source of radio fre- These magnetic field coils are.

A as power is taken from the space charge to. produce output frequency oscillations. The anode structure 3 is resonant to the output frequency and is tuned by means of an external circuit (not shown) to make it also resonant to the input frequency. The magnetic field serves to produce .the bending of electron paths which results in the rotating space charge. The tapering of the magnetic field with a minimum at the center of the tube in the region of the anode structure 30 serves to prevent loss of electrons due to motions in a direction parallel to the filament and each electron may be used for a relatively long time so that small cathode emission is required. The electrons thus always tend to be pushed to the location of the anode structure due to the tapering of the magnetic field. Output energy from the system is taken from a lead 36 which is arranged to be parallel to the thermionic cathode but positioned close to the structure 3B, preferably spaced a short distance from one of the spaces between the teeth, bars or turns of the annular anode ring.

Referring to Fig. 4a, it will be seen that the anode annular ring 35a is composed of a multiplicity cf flat top and flat bottom teeth or bars having spaces between adjacent top portions and between adjacent fiat bottom portions of the teeth.

Fig. 4b shows the annular anode ring 39D wherein the teeth have V-shaped sides. i

In Fig. 4c, the anode ring 38o is composed of a continuous metallic conductor generally in the form of a multiplicity of turns of wire.

The system of Fig. 3 as described above operates like that of Fig. 1, in that the spiral motion of the electrons from the cathode is produced solely by the ratio frequency input power from the source 3. However, a source ill of direct current voltage may be placed in series with the anode structure 30 and the cathode 42, to in crease the energy level at which electrons are utilized in producing oscillations, as in Fig. la.

What is claimed is:

l. An electron discharge device comprising an evacuated envelope having therein a multipole anode resonator structure, means passing through said structure along the longitudinal axis of said device and extending on both sides of said anode structure for a distance at least equal to the length of said structure measured along said axis for releasing electrons, and means adjacent said envelope for producing a tapering magnetic field whose intensity is appreciably less at the anode structure than at either side of said anode structure at the locations where said electrons are released, to thereby cause the released electrons to travel toward said anode structure.

2. A converter of radio frequency power at one frequency to radio frequency power at a higher frequency, including an electron discharge device comprising an evacuated envelope having therein a hollow multi-pole resonator anode structure,

associa and means on both sides of said ,anode structure for vproducing circulating electrons of high velocity traveling toward said anode structure, said means including a linear cathode extending through said hollow anode structure along the longitudinal axis of said device and appearing on both sides of said anode structure, and also including elements adjacent said envelope on both sides of said anode structure for producing a tapered magnetic eld whose intensity is appreciably less in the region of said anode structure .than on both sides thereof, and an output circuit comprising an element extending into the' interior of said envelope and coupled to said multi-pole resonator anode structure.

3. An electron discharge device frequency'converter comprising an evacuated envelope containing therein an annular resonant anode structure and an inner coaxially arranged cathode, said anode structure having a multiplicity of poles arranged in series therearo'und, a source of radio frequency energy coupled to diametrically opposite points on said anode structure so as to excite said anode structure with two halves in parallel for the input currents, said anode structure being resonant to an output frequency which is different from the frequency of said source, means for producing a tapering magnetic eld which is stronger on both sides than in the region of said anode structure, and an output circuit coupled to said anode structure for abstracting energy of a frequency to which said anode structure is resonant.

4. A frequency converter in accordance with claim 3, characterized in this that the poles of said anode structure are in the form of teeth with at edges.

5. A frequency converter in accordance with claim 3, characterized in this that the poles of said anode structure are in the form of turns of wire of sine Wave form.

6. A frequency converter in accordance with claim 3, characterized. in this that the poles of said anode structure are in the form of teeth with slanted edges.

7. An electron discharge device frequency converter comprising an evacuated envelope having therein a hollow multi-pole anode resonator structure, a pair of electron accelerator structures oppositely disposed with respect to both ends of f said anode structure, said accelerator structures each including a cathode element and a pluralityv of anodes symmetrically arranged around said cathode element, and means adjacent said envelope for producing a tapering magnetic field r which is more intense in the vicinity of said accelerator structures than in the region of said anode structure to thereby produce a rotating mass of electrons traveling at high velocity from both accelerator structures toward said anode resonator structure, a source of radio frequency currents coupled to the anodes of both accelerator structures, and an output loop coupled to said anode structure for deriving therefrom energy of a frequency higher than said source.

8. An electron discharge device converter of radio frequency power at one frequency to radio frequency power at a higher frequency comprising an evacuated envelope having therein a hollow multi-pole anode resonator structure, means within said envelope and outside the confines of said anode structure and oppositely disposed with respect to both hollow ends of said anode structure for producing electrons of high velocity traveling in spirals of increasing diameter toward 10 said anode structure, an input circuit of radio frequency energy coupled to "said converter, said anode structure being so constructed and having such dimensions that it is resonant to a Afrequency higher than the frequency of said radio frequency energy.

9. An electron discharge device comprising a magnetron having a hollow anode resonator, split-anode accelerator structures disposed on opposite sides of said anode resonator, `"each of said split-anode accelerator structures having a source of charged particles, means adjacent said device for producing a magnetic field having flux lines running parallel to the axes of said splitanode accelerator structures, whereby said 'accelerator structures supply high velocity electrons to opposite sides of said anode resonator.

l0. An electron discharge device frequency converter comprising an evacuated envelope having therein an anode resonator structure vand a source of electrons for each side of said anode' resonator structure, means adjacent to said envelope for producing a tapering magnetic feld having flux lines running substantially parallel to the axis of said anode resonator structure 'and whose intensity is appreciably less at the anode structure than at either side of said anode structure, a source of input alternating current coupled to an element within the envelope of said converter, and an output circuit coupled to said anode structure for abstracting energy of a frequency which is different than the frequency of said source.

1l. A frequency converter in accordance with claim 10, including `means coupled to an element of said converter for modulating a characteristic of the output energy.

4l2; In a magnetron oscillator device having means for producing an axial magnetic eld, a hollow anode resonator, accelerator electrode structures on both sides of the hollow ends of said resonator for setting up a rotating electron space charge, and a source of alternating current coupled to said accelerator structures and exciting said accelerator structures at a frequency substantially equal to the resonance frequency of electron motion within the axial magnetic field, said anode resonator being adapted to produce self-oscillations at a frequency different from the frequency of said source.

13. In an electron discharge device. means for establishing a rotating electron space charge comprising a source of electron emission, means adjacent said devicefor producing a magnetic field, means to subject electrons emitted from said source to a high frequency electric field at the approximate frequency of resonant electron motion in the magnetic field to thereby produce a rotating space charge, and means for removing the rotating space charge to another space region for utilization.

14. In an electron discharge device, means for establishing two rotating electron space charges comprising an anode resonator two sourcesv of electron emission on opposite sides of said anode resonator, means adjacent said sources for producing a magnetic field, means to subject electrons emitted from the two sources to a high frequency electric eld at the approximate frequency of resonant electron motion in the inagnetc field to thereby produce two rotating space charges, means for drawing the two rotating space charges together to form a combined rotating space charge within' the anode resonator,

11 and means to utilize the energy of the combined rotating space charge.

15.,In an electron discharge device, means for establishing a rotating space charge comprising a source of electron emission, means adjacent said device for producing a magnetic field, means to subject electrons emitted from said source to a high frequency electric field at the approximate frequency of electron resonance motion in the magnetic field to thereby produce a rotating space charge, means to remove the resulting electron space charge to another region having a different magnetic field intensity and therefore a different natural frequency of space charge rotation, and a hollow anode resonator located at said other region.

16. An electron discharge device frequency converter comprising an evacuated envelope having therein a multi-pole hollow anode resonator structure and sources of electrons on opposite sides of and outside the confines of said anode structure, means surrounding said envelope for producing a tapering magnetic field having flux lines running substantially parallel to the axis of said anode structure and whose intensity is less at the anode structure than on either side of said anode structure, means coupled to said sources of electrons for supplying thereto alternating current of a frequency differentfrom the resonant frequency of said anode resonator structure, and an output circuit coupled to said anode structure for deriving from said device energy of a frequency to which said anode resonator structure is tuned.

17. An electron discharge device frequency converter comprising an evacuated envelope having therein a hollow multi-pole anode resonator structure and sources of electrons on opposite sides of and outside the confines of said anode structure, means including coils individually surrounding said sources for producing a tapering magnetic field having flux lines running substantially parallel to the axis of said anode structure and whose intensity is less at the anode structure than on either side of said anode structure, a source of input alternating current coupled in electrically parallel relation to both of said sources of electrons, and an output circuit coupled to said anode structure.

18. An 'converter comprising an evacuated envelope having therein a hollow multi-pole anode resonator structure, a pair of electron accelerator structures oppositely disposed With respect to both ends of said anode structure, said accelerator structures each including a cathode element and a plurality of anodes symmetrically arranged 'around said cathode element, and means includv ing a coil individual to and surrounding each of converter comprising an evacuated envelope hav- `ing therein a hollow multi-pole anode resonator structure, a pair of electron accelerator strucelectron discharge device frequency tures oppositely disposed with respect to both ends of said anode structure, said accelerator structures each including a cathode element and a plurality of anodes symmetrically arranged `around said cathode element, and means including a coil individual to and surrounding each of said accelerator structures for producing a tapering magnetic field which is more intense in the vicinity of said accelerator structures than in the region of said anode structure to thereby produce a rotating mass of electrons traveling at high velocity from both accelerator structures toward said anode reasonator structure, a source of radio frequency currents coupled to anodes of both accelerator structures, the number of poles of said anode resonator structure providing oscillations in said anode resonator structure which have a frequency higher than the radio frequency of source, and an output circuit coupled to said anode resonator structure.

20. The method of producing high frequency oscillations which comprises circumferentially accelerating electrons to high velocities at locations oppositely disposed with respect to a central point, producing magnetic fields at said locations and at said central point, adjusting the magnetic eld at said central point to be smaller than the magnetic fields at said locations, causing said accelerated electrons to follow spiral paths of increasing diameter in an axial direction toward said central point, and resonating said spirally moving electrons at said central point at a frequency considerably higher than the circumferential frequency of said electrons.

21. An electron discharge device frequency converter comprising an evacuated envelope having therein a hollow multi-pole anode resonator structure, a pair of electron accelerator structures oppositely disposed with respect to both ends of said anode structure, said accelerator structures each including a cathode element and a plurality of anodes symmetrically arranged around said cathode element, and means adjacent said envelope for producing a tapering magnetic field which is more intense in the vicinity of said accelerator structures than in the region of said anode structure to thereby produce a rotating mass of electrons traveling at high velocity from both accelerator structures toward said anode resonator structure, a source of radio frequency currents coupled to the anodes of both accelerator structures, and an output loop coupled to said anode structure for deriving therefrom energy of a frequency higher than said source.

22. A frequency converter electron discharge device having a multi-pole anode resonator structure, means conductively coupled to diametrically spaced points on said structure for supplying said device with input power at one radio frequency, and means coupled to the space within the confines of said structure for abstracting power at another frequency, said structure being resonant to said last frequency.

23. An electron discharge device comprising an evacuated envelope containing therein an annular anode structure and an inner coaxially arranged cathode, said anode structure having a multiplicity of poles arranged in series around the anode structure, means for applying radio frequency energy to diametrically opposite points on said anode structure so as to excite said anode structure with two halves in parallel for the input currents, said poles being in the form of turns of Wire, the total annular length of said anode structure being substantially equal to a number of half waves, including unity, per turn for the frequency of operation of said device. the distance from the center of one turn to the center of an adjacent turn being substantially one-half Wavelength for the output frequency.

24. An electron-discharge device comprising: an anode structure; a cathode having an effective electron emitting surface, spaced from said anode structure; means for establishing an electric field between said cathode and said anode structure; said anode structure comprising at least one signal wave transmission network, and having signal input and output means cooperating therewith; and means for establishing magnetic flux lines parallel to said emitting surface `to said cathode.

25. An electron-discharge device comprising: an anode structure; a cathode having an effective electron emitting surface, spaced from said anode structure; means for establishing an electric eld between said cathode and said anode structure; said anode structure comprising at least one signal wave transmission network, and having signal input and output means cooperating therewith; and means for establishing magnetic flux lines perpendicular to a line normal to said emitting surface of said cathode.

26. An electron-discharge device comprising: an anode structure; a cathodehaving an effective electron emitting surface. spaced from said anode structure, said cathode being exposed to fields set up by high frequency energy supplied to said anode structure; means for establishing an electric field between said cathode and said anode structure; said anode structure comprising at least one signal wave transmission network, and having signal input and output means cooperating therewith; and means for establishingmagnetic flux lines parallel to said emitting surface of said cathode.

27. An electron-discharge device comprising:

` a cathode; an anode structure, spaced from said cathode, and including two spaced pairs of anode segments; said cathode and anode structure being adapted to have an electric field established therebetween; means, adjacent said cathode and said anode structure, adapted to establish a magnetic field therebetween perpendicular to and cooperable with said electric field, thereby to distribute electrons emitted by said cathode substantially uniformly in a rotating, annular stream; means, adjacent said cathode and said anode structure, adapted to cause said electron stream to drift axially past said pairs of anode segments; means, coupled to one of said pairs of anode segments, adapted to introduce high-frequency energy thereto, whereby as said electron stream drifts past the same, it is accordingly velocity-modulated, and as the velocity-modulated electron stream drifts past the other of said pairs of anode segments, oscillating voltages are induced between the segments thereof; and means, coupled to said last-named pair of anode segments, adapted to extract high frequency energy therefrom.

28. An electron discharge device comprising: a rst anode structure; a cathode having an effective electron emitting surface spaced from said first anode structure; means for establishing an electric eld between said cathode and said first anode structure; means for establishing magnetic flux lines parallel to said emitting surface of said cathode; a second anode structure axially spaced from said first anode structure; means for causing electrons from said cathode to drift axially past said first and second anode structures; and

signal input and output means cooperating with said first and second anode structures, respectively.

29. An electron device comprising a large anode structure and a small anode structure located within a single evacuated envelope, and spaced from each other along the axis of said envelope, a cathode extending within and between said anode structures, mea1; s coupled to said anode structures and to said cathode for applying a potential difference therebetween. means adjacent said envelope for applying a magnetic field to the space within and between said anode structures, and means coupled to said large anode structure for deriving alternating current energy therefrom.

30. A magnetron frequency converter comprising an envelope containing an anode structure including a multi-pole resonator structure, means coupled to said anode structure for supplying said converter with input power at one radio frequency and means coupled to said resonator structure for abstracting power from said converter at another frequency, said resonator structure being resonant to said other frequency.

CLARENCE W. HANSELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,114,114 Roberts Apr. 12, 1938 2,149,024 Lindenblad Feb. 28, 1939 2,247,077 Blewett et al. June 24, 1941 2,280,824 Hansen et al. Apr. 28, 1942 2,289,220 Smith July 7. 1942 2,305,883 Litton Dec. 22, 1942 2,409,222 Morton Oct. 15, 1946 2,431,688 Feenberg Dec. 2, 1947 2,423,716 McArthur July 8. 1947 

